Rice residue burning trajectories in Eastern India: Current realities, scenarios of change, and implications for air quality

 Emily Urban Cordeiro1, Douglas Hamilton, D.G. Rossiter et al.   |  

The Bihar State Government is aware of the risks associated with increasing agricultural burning, but the current extent of the practice and plausible scenarios of change have not yet fully informed state policies. The emergence of burning as a “locked-in” problem without simple solutions in Northwestern Indo-Gangetic Plain (IGP) highlights the importance of preventative action aimed at avoiding burning in the Eastern IGP rather than attempting to reverse the practice only after it is broadly adopted.

Rice residue burning occurs from October to December in the Northwestern Indo-Gangetic Plain (IGP), significantly contributing to poor regional air quality conditions during the fall and winter months. In the late fall period when regional air quality is at its nadir, rice residue burning contributes to as much as 42% of the fine particulate matter (PM2.5)—the most damaging air pollutant to public health. Other estimates for Delhi, suggest that fires contribute a range, depending on the method, of 7.0%–78% of the maximum observed PM2.5 enhancements (i.e. pollution levels above an anthropogenic baseline) during the post-monsoon burning season.

Estimates suggest that PM2.5 alone causes as many as 16 200 premature deaths annually in New Delhi, while also contributing to a host of additional acute and chronic public health concerns ranging from respiratory infections to lung cancer. Residue burning also increases greenhouse gas emissions while degrading soil health and the production potential of agricultural systems.
While the practice of rice residue burning is pervasive in the dominant rice-wheat systems of the Northwest IG, it is much less common in these same cropping systems in the Eastern IGP region of India (i.e., the states of West Bengal, Bihar, and adjacent areas of Uttar Pradesh).

In the Northwest, factors such as combine harvesting, a shortening planting window for wheat, and crop intensification help perpetuate this practice. Despite dedicated efforts to reduce burning through a combination of financial incentives and legal sanctions, there is little evidence from the Northwest that the practice is receding. Just as worrisome, drivers that have shifted the valorization of rice residues from a resource to a waste product in the Northwest may now be emerging in the Eastern IGP.

Given its relatively high rates of rural poverty and capacity for agricultural-led growth, the Eastern IGP is a development and food security priority region for the Government of India through initiatives like Bringing the Green Revolution to Eastern India (BGREI) that focus on enhancing the productivity of agricultural systems through technological change.

Program initiatives in Bihar have included efforts related to direct seeded rice, zero tillage wheat, distribution of improved seed varieties, and assistance for farm machinery and implements. The densely settled state of Bihar is of particular interest with the 2019 census documenting a population exceeding 124 million. With the state’s capital and largest city, Patna, already among the most air-polluted metropolitan regions in India, a rapid expansion of residue burning may lead to significant consequences for public health.

At present, Patna PM2.5 concentrations exceed the daily NAAQS (National Ambient Air Quality Standards) threshold around 77% of the winter days and contribute an estimated 1% to all-cause mortality rates.

The Bihar State government is aware of the risks associated with increasing agricultural burning, but the current extent of the practice and plausible scenarios of change have not yet fully informed state policies. The emergence of burning as a ‘locked-in’ problem without simple solutions in the Northwest IGP highlights the importance of preventative action aimed at avoiding burning in the Eastern IGP rather than attempting to reverse the practice only after it is broadly adopted.

Technological lock-in is present in many economic sectors, including agriculture, and is perpetuated by a series of dependency factors that make the technology difficult to disentangle from other dimensions of the system. For example, as access to mechanization technologies such as combine harvesting expands, burning is often practiced post-harvest as a quick and inexpensive method for clearing loose residues that remain in the field.

New combine users often become ‘locked-in’ to burning because transitions to the combine have been made and there are few economically viable alternatives for residue management. Consequently, burning becomes an enabler for broader technological change that is difficult to displace.

By conceptualizing the practices of burning as a space-time process of technological change, it should be possible to make inferences about future spread based on historical patterns. Similar projection models have been developed for disease epidemiology and the biogeography of invasive species. The spread of burning practices can be conceptualized as having characteristics of epidemic models, where infection (i.e., adoption) emerges due to proximity, as well as ‘influencing factor’ models of technological change, where transitions are triggered by an individual’s varying goals and needs independent of proximity.

Therefore, this research has three objectives: (1) characterize historical rice residue burning trends since 2002 over space and time in Bihar, (2) project future burning trajectories to 2050 under ‘business as usual’ and alternative scenarios of change, and (3) simulate air quality outcomes under each scenario to describe implications for public health.

By employing an integrative assessment framework that centers on public health, this study endeavors to provide an evidence base to support early action for avoiding pervasive agricultural burning in the Eastern IGP before the practice “locks in.”

In the context of systems agronomy for global development, there have been limited examples of ex ante research that seeks to understand and address a problem before it fully materializes. This work represents the first comprehensive effort to characterize current rice residue burning trends in the Eastern IGP and to anticipate different development trajectories.

Through a naïve point pattern forecasting approach coupled with the scenario outputs derived from the Community Earth System Model version 2.1 (CESM2.1.0), we characterize the spatial nature of the phenomenon, the current trends across historical time starting in 2002, and the air quality implications mid-century if the progression of burning is not stopped.

The air quality impact of burning at present levels can be easily overlooked, yet the growing trend and the peak damage potential should be at the forefront of policy conversations at the agriculture and public health nexus. Without creative and urgent interventions to stop burning, the mid-century reality could result in an extensive winter air quality crisis, particularly for the residents of Patna.

Read the study:
Cordeiro UB, Hamilton DS, Rossiter DG et al (2024) Rice residue burning trajectories in Eastern India: current realities,
scenarios of change, and implications for air quality. Environ. Res. Lett. 19 014006

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